Known methods for producing erythro-3-amino-1,2-epoxy compounds include the following ones:
(1) a method comprising reacting an (S)-.alpha.-aminopropanal derivative, which has been synthesized from an (S)-.alpha.-amino acid, with dimethylsulfonylmethylide [see J. Org. Chem., 50, 4615-4625 (1985)]; PA1 (2) a method comprising reducing an (S)-3-amino-1-chloro-2-butanone derivative, which has been synthesized from an (S)-.alpha.-amino acid, with a ketone followed by cyclization (see EP 346847); and PA1 (3) a method wherein the reaction proceeds via (S)-3-amino-2-substituted-1-butanol which has been synthesized from an (S)-.alpha.-amino acid (see EP 432694).
In the above methods, however, it is generally needed to construct a novel asymmetric carbon atom and the reaction cannot usually proceed stereo-specifically. Accordingly it is unavoidable that unnecessary diastereomer(s) are thus formed. In fact, the above methods each achieves only a poor selectivity. To obtain a desired product with a high optical purity, therefore, optical purification procedures (for example, optical resolution or silica gel chromatography) are effected, which results in a low yield and a poor operating efficiency. Thus these methods are hardly regarded as a practically usable one.